Voltage induced creepage and pin to pin clearance of an integrated circuit (IC) is critical for high voltage and isolation products. Creepage distance is the shortest distance separating two conductors as measured along an insulating surface touching both conductors. The Institute for Interconnecting and Packaging Electronic Circuit (IPC) has promulgated a standard entitled “Generic Standard on Printed Board Design” IPC2221A, May 2003, which is intended to provide information on the generic requirements for organic printed board designs.
Creepage distance and clearance is critical for high voltage and isolation products. The required creepage distance, as stated in IPC2221A, is determined by the voltage difference between the two conductors, the pollution degree in which the isolation circuit will be used, and the insulation material. This requirement is set to prevent electrical breakdown on the surface of the insulating material (a large voltage differential creates a conductive leakage path across the insulating surface) and arcing which results in IC performance degradation. The distance requirement often exceeds the standard pin to pin pitch of a JEDEC package.
One solution is to use a leadframe for the IC in which one or more pins are depopulated in order to increase the distance between the remaining pins. Another solution is to use a larger package and leadframe for the IC that has a greater pin to pin pitch distance.
Other features of the present embodiments will be apparent from the accompanying drawings and from the detailed description that follows.